(1) Field of the Invention
The present invention pertains to an electronic ignition system which uses an electric arc to ignite the propellant in a personal firearm and a firearm using such a system.
(2) Background of the Invention
Hunting and shooting with muzzleloaders is rapidly gaining popularity as a sport. The muzzleloader is essentially a primitive rifle, shotgun, or pistol, based on designs used during the early days of America and lacking the effective range of more modem center fire rifles and the speed of reloading available to cartridge firearms. Because of their popularity, many states have adopted special muzzleloader seasons for hunting with these weapons to allow sportsmen using them (who generally have to get much closer to their targets and be more sure of their aim than those using modem cartridge rifles) to be able to effectively hunt. With the creation of these special seasons, many hunters are moving from more modem rifles to muzzleloaders to take advantage of the special season.
A muzzleloader is also known as a “black powder” firearm due to their use of a different chemical formulation of gunpowder commonly called black powder (which does not specifically relate to the color). As opposed to a more modem firearm which is loaded with a cartridge at the breach, in a muzzleloader loose powder (or powder pellets) and the projectile are loaded into the barrel via the muzzle of the gun and tamped against the breach plug. The powder used is black powder, or more modem substitutes for black powder such as, but not limited to, Pyrodex™ or Triple 7™ manufactured by the Hodgdon Powder Company. The modem smokeless powder used in cartridges and shotgun shells, however, cannot be safely used with most muzzleloaders.
Black powder firearms currently use one of two systems to ignite the powder charge and discharge the projectile from the firearm. The most primitive type of firearm is a flintlock which utilizes a flint which is thrown forward by the hammer (which is generally mounted on the side of the firearm) into a piece of steel generating a spark. The spark is used to ignite a priming pan of fine black powder. The burning priming powder sends a spark through a touchhole which is a small hole in the side of the firearm's barrel. The spark then ignites the main powder charge in the barrel which discharges the firearm.
More modern black powder firearms are caplocks. The traditional caplock still has the hammer on the side of the gun but the flint, steel, and priming pan are eliminated. Instead the hammer swings into a percussion cap which contains an explosive fulminate of mercury. The percussion cap is resting on a nipple through which the spark travels to reach the main charge in the barrel. The most modem type of muzzleloader was developed to provide more effective discharge. This is an in-line caplock which operates in the same manner as a traditional caplock but instead of having the hammer, nipple, and cap on the side of the gun, they are placed in line with the barrel. The in-line caplock is essentially a modernized muzzleloader which retains the firing and loading profile of a traditional muzzleloader with a more modem ignition system.
By their very nature, muzzleloaders are essentially primitive firearms, and for many hunters and shooters this primitive nature is part of their appeal. The weapon's decreased effective range requires the hunter to be a more effective stalker. Further, the time it takes to reload a muzzleloader generally means that the hunter gets only a single shot at a target requiring them to be sure of their aim before firing. There is also polarization in muzzleloading hunting. Some wish to only utilize traditional firearms and are very interested in the nostalgia (these tend to use flintlocks and sidelocks to “accurately” represent primitive hunting). Others are continuously modernizing the “primitive” firearm to provide for improved triggering, safety, and accuracy, while still keeping the tradition of loading powder and shot down the muzzle instead of using a cartridge to provide for the long reload time and single shot capability. These hunters generally use in-line caplocks and are always interested in improving on the design without altering the basic loading and shooting characteristics of the firearm. Many of these improvements relate to modernized projectiles that provide improved flight characteristics, modem propellants which provide improved propulsion and ignition and the in-line caplock design which provides for surer ignition.
Because the powder, projectile and percussion cap are separately loaded for each shot and are not subject to mechanical assembly as in a cartridge rifle, muzzleloaders are particularly vulnerable to conditions known as hangfire or misfire where the gun does not discharge immediately upon the trigger being pulled. A misfire occurs when the gun does not fire at all. A hangfire occurs when the cap or flint successfully flames and sends sparks toward the main charge, but the main charge does not ignite for a few seconds after the trigger is pulled. A hangfire can be particularly problematic because the action of the hammer may startle the intended target, and the gun may discharge later without the intended target in the field of fire. Further, a hangfire may result in the user positioning the gun unsafely, thinking the gun has misfired, prior to it discharging.
Most of these problems result from imperfect operation of the ignition systems. In a cartridge firearm, the ignition system and primary propellant are both encased in the cartridge which allows them to be in direct contact when the gun is fired. Therefore, hangfires are unlikely. In a muzzleloading firearm, there is always some distance that the flame needs to travel to get from the cap or priming pan to the primary propellant. The travel time of the spark can be undesirably increased if the conditions are wet or if there is powder in the hole which must burn, essentially like a fuse, for the spark to reach the primary propellant.